Rock drill



Feb. 28, 1928. 1,660,528

F. w. RUDLIN ROCK DRILL m on. so. 1926 I N VEN TOR.

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FREDERICK W. HUD-LIN, OF PHILLIPSBURG, 'NEW JERSEY, ASSIGNOR TO. INGERSOLL- RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

. ROCK DRILL.

Application filed October so, 1926. Serial No. 145,274.

This invention relates to rock drills, but more particularly to a distribut ng valve for fluid actuated rock drills of the hammer type. v

The objects of the invention are to obtain utilize exhaust pressure fluid for holding the valve in thrown position. I

Other objects will bein part obvious and in part pointed out hereinafter. I

The invention consists of the combination of elements, features of construction and arrangement of parts having the general mode of operation substantially as hereinafter pointed out in the appended claims and illustrated in the accompanying drawings, in which a Figure l is a longitudinal elevation in section of so much of a rock drill as will serve to illustrate the invention, and

Figure 2 is a similar view showing the valve and the piston in another position which they may assume in operation of the drill.

Referring to the drawings, A designates a cylinder closed at its front end by a bushing B and at its rearward end by a back head C. Disposed within the cylinder A is a hammer piston D having in this instance a plain reduced extension E which cooperates slidably with a bore F in the bushing B.

Disposed on the cylinder A is a valve chest Gr having a longitudinal bore H therethrough. Bushings J are disposed in the ends of the bore H and are provided at their outer ends with flanges K which, seatv into recesses L formed in the ends of the bore H. The bushings Jere suitably bored to form a valve chamber 0 closed in this instance at its ends by plugs P having suitable flanges Q to abut the ends of the'bushings J. The bushings J and. the plugs P may be held in assembled position in any suitable manner.

In the present instance pressure fluid may be admitted from a suitable source of supply to the valve chest G through a connection R from which connection branch in opposite directions, supply passages S. These supply passages S communicate with the valve chamber 0 through ports T and U formed in the rearward and front bushings J respectively. Ports and W preferably formed diametrically opposite the ports T chamber 0. Similar ports care formed in the opposite sides of the bushings J to register with main exhaust ports. d in the valve chest leading to the atmosphere.

Disposed within the valve chamber 0 is a distributing valve 6 having in this instance a central head f and end heads 9 and h. The heads are of the saine diameter and the outer heads g andh control both the admission of pressure'fluid from the supply passages S to the ends of the cylinder and also the exhaust of-pressure fluid from the ends of the cylinder to the atmosphere, while the central head f serves to prevent the simultaneous exposure of the inner ends of the heads 9 and hi to pressure fluid and which pressure fluid would act to centralize the valve in the valve chamber. Theend heads 9 and It are preferably so spaced with respect to each other that the valve will. be

unable at any time to completely cover both the inlet. ports" which they control. However, the end heads are of'such lengththat either head may simultaneously cover the inlet ports and the exhaust ports'which they are adapted to control.

Leading frim a point rearwardly of the median line of the cylinder to the rearward end of the valve chamber O is a. passage 3' bleeder passages 0 are formed .in the plugs:

P to provide an outlet for any pressure fluid which may leak pa'stthe end heads to the ends of the valve chamber 0. v

'In the operation of the device, with the parts in the position illustrated in Figure 1, pressure fluid entering the connection It will flow through the supply passages 8,--

through the port T, into the valve chamber 7 0 between the heads f and g thence through the port V, the passage Z and through the inlet passage X to the rearward end of the cylinder to impel the piston forwardly. As the piston proceeds on its forward stroke, it will uncover the kicker passage j, whereupon pressure fluid will flow through said passage j to the rearward end of the valve chamber 0 and move the valve e forwardly to the position illustrated in Figure 2, thus covering the ports T and -V and simultaneously uncovering the ports I) and 0 to permit the escape of pressure fluid from the rearward end of the cylinder through these channels and throughthe main exhaust port at and the end of the valve chamber to the atmosphere. The exhaust fluid thus flow ing through the valve chamber will act against the forward end surface of the valve and hold said valve in its rearward position. While the valve is in its rearwardmost position the front end of the cylinder will be opened to the atmosphere so that any air which may exist in the front end of the cyl inder will be expelled through the front inlet passage Y, the ports 6 and c and the main exhaust port (Z to the atmosphere,thus preventing the upbnilding of compression in the front end of the cylinder.

Upon the forward movement of the valve 6 the front end head h will uncover the front supply passage S to admit pressure fluid between the heads 9 and 7t and through the port W, the front passage Z and the front inlet passage Y to the front end of the cylinder to impel the piston rearwgardly.

, During the rearward stroke of the piston the front kicker passage is will be uncovered and pressure fluid will then pass through this assage to the front end of the valve cham er 0 and throw the valve 6 to its rearwardmost limiting position. In the rear ward position of the valve communication between the ports U and WV will be cut off by the head it and the front end of the .cylinder will again be opened to the atmosphere through the inlet passage Y, the ports I) and c and the main exhaust port 03, thus completing the cycle of operations.

From the foregoing, it will be observed that the valveis thrown by live pressure fluid and is. held in thrown position by pres-- sure fluid exhausting from the cylinder. This is a desirable advantage in valves of this type for the reason that the valve may be thrown at the most desirable period in the cycle of operations. e

I claim:

1. In a fluid actuated rock drill, the combination of a cylinder, a hammer piston in the cylinder, a valve chest having a valve chamber and a pair of supply passages, inlet from opposite sides of the median line of the cylinder to corresponding ends of the valve chamber for conveying pressure fluid to the ends of the valve chamber for throwing the valve, said valve beingheld in thrown position by exhaust fluid acting on the end surfaces of the valve. i

2. In a fluid actuated rock drill, the combination of a cylinder, a hammer piston in the cylinder, a valve chest having a valve chamber and a pair of supply passages, inlet passages leading from the valve chamber to the ends of the cylinder, ports in the valve chest for exhaustin pressure fluid from the ends of the cyhn er into the ends of the valve chamber, main exhaust passages leading from the ends of the valve chamber for conveying; such exhaust fluid to the at mosphere, a valve in the valve'chamber having a central head and end heads, the end heads controlling the inlet and exhaust passages and spaced with respectto each other to prevent coincident covering of the inlet passages and the central head serving to prevent simultaneous exposure of the inner surfaces of the end heads to pressure fluid, kicker ports leading from opposite sides of the median line of the cylinder to corresponding ends of the valve chamherfor conveying pressure fluid to the ends of the valve chamber for throwing the valve, the

valve being held in thrown position by exhaust pressure fluid passing through the ends of the valve chamber and acting against the end surfaces of the valve, and bleeder ports leading fromthe ends of the valve chamber to the atmosphere. 7

In testimony whereof I have signed this specification. FREDERICK W. RUDLIN. 

